CA1230645A - Light load adjust apparatus for electric meter - Google Patents
Light load adjust apparatus for electric meterInfo
- Publication number
- CA1230645A CA1230645A CA000476141A CA476141A CA1230645A CA 1230645 A CA1230645 A CA 1230645A CA 000476141 A CA000476141 A CA 000476141A CA 476141 A CA476141 A CA 476141A CA 1230645 A CA1230645 A CA 1230645A
- Authority
- CA
- Canada
- Prior art keywords
- carrier
- light load
- adjustment screw
- disk
- adjustment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
- G01R11/02—Constructional details
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Breakers (AREA)
- Magnetic Treatment Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
LIGHT LOAD ADJUST APPARATUS FOR ELECTRIC METER
A light load adjustment for an electric meter includes a frame attachable to a core of a voltage coil and a pole-shading element slideable with respect to the frame. The pole-shading element includes a windowed plate or a pair of tabs interposeable between the core of the voltage coil and the rotatable disk and effective to change the direction and magnitude of the torque applied to rotatable disk of the electric meter at light load.
A single adjusting screw for the light load adjustment is placed in one of its two alternative positions. In either of its two alternative positions, rotation of the head of the adjusting screw by a worker facing the head produces a displacement of the windowed plate or tabs which tends to change the disk speed in a sense which is consistent with the convention for the relationship between the direction of rotation of an adjustment and the change in disk speed.
LIGHT LOAD ADJUST APPARATUS FOR ELECTRIC METER
A light load adjustment for an electric meter includes a frame attachable to a core of a voltage coil and a pole-shading element slideable with respect to the frame. The pole-shading element includes a windowed plate or a pair of tabs interposeable between the core of the voltage coil and the rotatable disk and effective to change the direction and magnitude of the torque applied to rotatable disk of the electric meter at light load.
A single adjusting screw for the light load adjustment is placed in one of its two alternative positions. In either of its two alternative positions, rotation of the head of the adjusting screw by a worker facing the head produces a displacement of the windowed plate or tabs which tends to change the disk speed in a sense which is consistent with the convention for the relationship between the direction of rotation of an adjustment and the change in disk speed.
Description
Eye LIGHT LOAD ADJUST APPARATUS FOR ELECTRIC lottery BACKGROUND
The present inversion relates to electric meters and, more particularly, to a light load adjustment or electric meters.
Conventional electric meters employ an aluminum disk driven as a rotor of a small induction motor by an electric field at a speed which is proportional to the electric power bug consumed by a load. Geared dials or cyclometer disc integrate the disk motion to indicate the total energy consumed, conventionally measured in kilowatt hours (one kilowatt hour equals one thousand watts of power consumption for one hour).
The speed of the rotor disk is controlled by the competing torques of a rotating electric field and ox eddy current losses induced on the disk by rototill within the influence of a permanent magnet.
The notating electric lulled us produced by one or more voltage cowls on one side of the disk and one or more current coils on the other side of the disk.
I
The present inversion relates to electric meters and, more particularly, to a light load adjustment or electric meters.
Conventional electric meters employ an aluminum disk driven as a rotor of a small induction motor by an electric field at a speed which is proportional to the electric power bug consumed by a load. Geared dials or cyclometer disc integrate the disk motion to indicate the total energy consumed, conventionally measured in kilowatt hours (one kilowatt hour equals one thousand watts of power consumption for one hour).
The speed of the rotor disk is controlled by the competing torques of a rotating electric field and ox eddy current losses induced on the disk by rototill within the influence of a permanent magnet.
The notating electric lulled us produced by one or more voltage cowls on one side of the disk and one or more current coils on the other side of the disk.
I
2 11-ME-128 The voltage golfs conventionally include a large number ox turns ox fine insulated wire wound on the center leg ox an E-shaped laminated core. The current golfs conventionally tncludo a small number ox (two or more) turns ox heavy conductor on a U-shaped laminated core. The voltage and current golfs are arranged to produce a torque in the disk which is equal to the product of the fine voltage and the load current; that us, the load power.
In order to calibrate the disk speed, adjustments are provided or pull load and light load among others not ox interest here. The pull load speed of the disk at rated voltage and a test current is factory adjusted by increasing or reducing the magnetic flux ox the permanent magnet until the desired relatLonshlp between loud power and disk speed is achieved. A manual pull load vernier adjustment permits channeling of a portion of the magnetic flux ox the permanent magnet to provide final control ox disk speed at pull load.
Even when the disk is adjusted Pro precise speed at full load, core non-llnearlties, fiction and mechanical or magnetic dlssymmetrles may produce errors in the relationship between load and disk speed at light loads ox, or example, about 10 percent ox pull load. A light load adjustment is provided to vary the torque applied to the disk at fight load either in the direction ox motion or against the direction ox motion until the desired power and speed relationship is attained. The fight load adjustment may conventionally include a fight ., .
I
In order to calibrate the disk speed, adjustments are provided or pull load and light load among others not ox interest here. The pull load speed of the disk at rated voltage and a test current is factory adjusted by increasing or reducing the magnetic flux ox the permanent magnet until the desired relatLonshlp between loud power and disk speed is achieved. A manual pull load vernier adjustment permits channeling of a portion of the magnetic flux ox the permanent magnet to provide final control ox disk speed at pull load.
Even when the disk is adjusted Pro precise speed at full load, core non-llnearlties, fiction and mechanical or magnetic dlssymmetrles may produce errors in the relationship between load and disk speed at light loads ox, or example, about 10 percent ox pull load. A light load adjustment is provided to vary the torque applied to the disk at fight load either in the direction ox motion or against the direction ox motion until the desired power and speed relationship is attained. The fight load adjustment may conventionally include a fight ., .
I
3 11-ME-128 load plate of co~du~tlve or magnetic material having a rectangular window punched there through or it may lncluds a bar hazing a pair ox tabs of magnetic material interposed between the outer legs of the core ox the voltage coil and the disk. When. the window or the tabs are symmetrical to the pole ox the voltage coil, they co~trlbute zero torque to the disk. The plate or tabs may be displaced parallel to the plane ox the disk so that they align with, or shade, one ox the outer legs ox the E-shaped core ox the voltage coil more than they shade the other outer leg. This generates a dissymmetry in the magnetic flux and the resultant torque, produced by the voltage coil which has a magnitude related to the difference in shading ox the two outer legs and a direction related to the direction in which the poop or tabs are adjusted.
The light load adjustment is conventionally controlled by rotating a screw which thereby provides a limited translation ox the light load plate or tabs. A rigid con~entlo~ has been adopted or the direction ox rotation ox controls used or adjusting disk speed. According to this convention, turning a control in the clockwise direction wise the disk notation and turning a control in the counterclockwise direction speeds up the disk rotation.
Some electric meters employ two or three voltage c0119 in order to combine the power usage data from two or more phases ox the load power into notation of a single disk. In one such arrangement, two voltage coils are arranged 180 degrees apart ~3[3~
The light load adjustment is conventionally controlled by rotating a screw which thereby provides a limited translation ox the light load plate or tabs. A rigid con~entlo~ has been adopted or the direction ox rotation ox controls used or adjusting disk speed. According to this convention, turning a control in the clockwise direction wise the disk notation and turning a control in the counterclockwise direction speeds up the disk rotation.
Some electric meters employ two or three voltage c0119 in order to combine the power usage data from two or more phases ox the load power into notation of a single disk. In one such arrangement, two voltage coils are arranged 180 degrees apart ~3[3~
4 EYE
about the clrcum~erence ox the disk. Each of thy voltage coils may be provided with it own fight load adjustment for improved precision under asymmetric loading ox the phases. It is con~enlent to position the fight load adjustment screws for both voltage golfs aqualung toward the front ox thy meter so that a worker has easy access to them prom a single location. However, their locations spaced 180 degrees apart about the circumference of the disk requires that the displacements of the light load adjustments must be in opposite directions with respect to the worker in order to obtain thy same change in disk speed. This causes a problem in meeting the standard that the direction of rotation ox the adjustment scarves must produce the same direction of change in disk speed.
Similar problems exist when, or example, three voltage golfs are spaced 120 degrees apart about the disk.
One way that such adjustment problems might be solved is to provide two different adjustment linkages On with a rlght-hand threaded screw and the other with a left-hand threaded screw. In this arra~gem~nt, one ox the adjustment linkages may be used on one ox the voltage transformers and the other adjustment ll~kage may be used on the other voltage transformer. This technique suffers the cost disadvantage that two dlffer~nt linkages, and perhaps even two dl~ierent voltage transformers assembled with their respective linkages, must be manufactured and stocked.
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about the clrcum~erence ox the disk. Each of thy voltage coils may be provided with it own fight load adjustment for improved precision under asymmetric loading ox the phases. It is con~enlent to position the fight load adjustment screws for both voltage golfs aqualung toward the front ox thy meter so that a worker has easy access to them prom a single location. However, their locations spaced 180 degrees apart about the circumference of the disk requires that the displacements of the light load adjustments must be in opposite directions with respect to the worker in order to obtain thy same change in disk speed. This causes a problem in meeting the standard that the direction of rotation ox the adjustment scarves must produce the same direction of change in disk speed.
Similar problems exist when, or example, three voltage golfs are spaced 120 degrees apart about the disk.
One way that such adjustment problems might be solved is to provide two different adjustment linkages On with a rlght-hand threaded screw and the other with a left-hand threaded screw. In this arra~gem~nt, one ox the adjustment linkages may be used on one ox the voltage transformers and the other adjustment ll~kage may be used on the other voltage transformer. This technique suffers the cost disadvantage that two dlffer~nt linkages, and perhaps even two dl~ierent voltage transformers assembled with their respective linkages, must be manufactured and stocked.
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5 SUE
OBJECTS AND SEYMOUR OF THE INVENTION
Accordingly, it is on object of the inrentlon to provide a fight load adjustment or an electric meter which overcomes the drawbacks ox the prior art.
It it a further object of the ln~entlon to provide a fight load adjustment for an electric meter which provides the same sense ox adjustment of disk speed or a given direction ox adjustment notation regardless ox the end of the voltage golf at which the adjustment is performed.
Briefly stated, the present invention preludes a fight load adjustment for an electric meter which includes a frame attachable to a core of a voltage coil and a pole-shading element slldeable with respect to the frame. The pole-shadlng clement includes a windowed plate or a pair of tabs lnterposeable between the core ox thy voltage golf and the rotatable disk and effective to change the direction and magnitude of the torque applied to rotatable disk ox the electric Peter at light load.
A single adjusting screw for the fight load adjustment is placed lo eye I its two altcrnatlYe positions. In either ox its two alternative positions, notation of the head of the adjust screw by a worker aqualung the head produces a displacement ox the windowed plate or tabs which tends to change the disk speed in a sense which it consistent with the con~entlon or the relationship between the directioll of rotation of an adjustment and the change in disk speed.
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. 6 Lowe According to an embodlms~t ox the ln~entio~, there is provided a fight load adjustment ton an electric mater, the electric meter being of the type including at least a voltage golf having a core and a rotatable disk rotatable by a magnetic field at least partly produced by the voltage golf, the core having at least first and second legs disposed within a magnetic influence of the disk, comprising a frame rigidly attachable to the core, a carrier, means for slid ably guiding the carrier on the frame along an axis parallel to a plate ox the disk, pole-shadlng means on the carrier disposable Betsy the first and second legs and the disk and e~ectLve ton at least partly distorting the magnetic field whereby a fight load adjustment torque is applied to the disk, a single light load adjustment screw, first and second alternative locations for the adjustment screw in the frame and the carrier, the first and second locations permitting adjustment access to the adjustment screw prom first and second different locations with respect to the core, the first and second different locations being 180 degrees apart about the core and means at the first location or dlsplaci~g the carrier in a first direction along the axis in response to rotation of the adjustment screw in a first rotational direction and or displacing the carrier in a second opposite direction along the axis in response to notation of the adjustment screw in a second rotational direction, and means at the second location or displacing the carrier in the same first direction along the axis in response to rotation of the adjustment screw in the same first notational 3~6~`~
direction and for displacing the carrier I the same second direction along the axis in response to rotation ox the adjustment screw in the same second notational direction whereby the rotation ox the adjustment screw in one ox the first and second notational directions produces a displacement ox the carrier in the same direction regardless ox whether the single adjustment screw is disposed in the lust or the second alternate locations.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanyl~g drawings, in which like reverence numerals designate the same elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial view ox an electric Peter including a light load adjustment according to an embodiment of the invention.
Fig. 2 is a close-up perspective view ox the light load adjustment ox Fig. 1.
Fig. 3 is a cross cyclone taken along II-II
in Fig. 2 showing the adjustment screw in one of its two alternative locations.
Fig. is a cross section taken along III-III
in Fig. 2 showing the adjustment screw on the other of its two alternate locations.
....
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring Dow to Fig. 1, there is shown, generally at 10 an induction motor in an electric meter. Induction motor 10 includes a voltage cowl 12 on one suds of a rotatable aluminum disk 14 and a current golf 16 on the other side ox rotatable aluminum disk 14. As is conventional, current golf 16 includes a small number ox turns of a heavy conductor 18 passing through a U-shaped magnetic core 20. Typically, two or more turns ox current coil 16 are employed. The load current, or a current proportional to the load current, passes through current coil 16 and thereby produces a magnetic flux in U-shaped magnetic core 20.
Voltage coil 12 consists ox a large number of turns ox a lye insulated wire wound on a center leg 22 of an E-shaped magnetic core 24. The voltage appearing across the load is applied to voltage golf 12. Outer legs 26 and 28 ox Escaped magnetic core 24 are disposed adjacent rotatable aluminum disk 14 generally opposed to legs 30 and 32 ox current coil 16. A light load adjustment 34 is axed to outer legs 26 and 28 adjacent rotatable aluminum disk 14 using, or example, a bolt or rivet 36 through each ox outer lets 26 and 28. The load voltage applied to voltage golf 12 induces a magnetic flux in E-shaped magnetic core 24 which, when combined with the magnetic flux produced in U-shaped magnetic core 20 by the current in current golf 16, produces a torque on rotatable alul~lnum disk 14 which is proportional ~;23~
to the product ox the load current and the ~oltag0.
Although light load adjustment 34 may be of the conductl~e plate or the tab type without departing from the scope ox the invention, or concreteness of description, fight load adjustment 34 is chosen to be ox the type hazing a par ox tabs 38 and 40 of magnetic material overlaying outer legs 26 and 28 respectively Referring now also to Fig. 2, light load adjustment 34 consists of a frame 42 and a tab carrier 44. Frame 42 is affixed to outer lugs 26 and 28. Tab carrier 44 is transversely movable with respect to frame 42 and E-shaped magnetic core 24 to thereby displace tabs 38 and 40 in a direction parallel to the plane of rotatable aluminum disk 14.
Frame 42 includes a transverse bar 46 secured parallel to outer legs 26 and 28 and first and second platform portions 48 and 50 hulling upper beaning surfaces 52 and 54 respecti~aly disposed at fight angles to the plane ox transverse bar 46. Platform portions 48 and 50 are preferably integrally formed with transverse bar 46 using, or example, an appropriately shaped piece of sheet metal in which right angle bends (not shown) may be made to position upper bearing surfaces 52 and 54 in the positions shown. A dependent lop 56 is wormed by a fight angled bend 58 at an end ox upper beaning surface 52 wearer the center of E-shaped magnetic core 24. A
dependent lip 60 is formed by a fight angled bend 62 at an end ox upper beaning surface 54 further from the center of E-shapad magnetic core 24.
Tab carrier 44 includes a connecting bar 64 having a pair of aligned longltud~nal slots 66 and 63 I
thrill hounder rivet 70, affixed in upper beaning surface 52 passes guidlagly through longltudi~al slot 66. Similarly, a shoulder rivet 72 passes guidingly through longitudinal slot 68~ Tab carrier 44 is per~ltted to displace a limited distance transversely in the guldanc0 direction defined by longitudinal slots 66 and 68. A support portion 74 at one end of tab carrier 44 overlies upper beaning surface 52 ox frame 42. Similarly, a second support portion 76 at the other end ox tab carrier 44 overlies upper beaning surface 54 of frame 42. A dependent lip 78 is formed at an end ox support portion 74 further prom the center of shopped magnetic core 24. A dependent tip 80 is wormed at the end ox support portion 76 nearer to tile center of E-shaped magnetic core 24.
A single adjusting screw 84 is employed in one of two alternate locations in light load adjustment 34 to position tab carrier 44 with respect to outer legs 26 and 28. One of the alternate locations for adjustment screw 84 is shown in solid line between dape~dent tips 60 and 80. The other of the alternate locations for adjustment screw 84 is shown in dashed line between dependent tips 56 and 78.
Referring now to the cross section in Fig. 3 showing adjusting screw 84 I its solid fine po81tlon between dependent lip 60 and dependent lip By at the right side of Figs. 1 and 2, it will be noted that adjusting screw 84 includes an enlarged head 86 abutting one surface of dependent tip 60 and a shaft I passing through a hole 90 in dependent tip 60. A
groove 92 retains a C washer 94 against the other ~3~6~i surface of dependent lip 60 to thereby permit rotation of adjustln~ screw I without permitting it to displace with respect to dependent lip 60 that is, with respect to frame 42). A threaded hole 96 thread ably engages a threaded portion 98 on adjusting screw 84. Rotation of adjusting screw 84 is effective to displace dependent lip 80, and the remainder of tab carrier 44 with it, by changing the separation D between dependent lip 60 and dependent tip 80. If adjusting screw 84 has, for example, a left hand thread, rotation ox adjusting screw 84 in the counterclockwise direction is effective to reduce the separation dimension D and to thereby displace tab carrier 44 in the ruptured direction indicated by a solid arrow 100.
Referring now to Fig. 4, showing adjusting screw 84 in its alternate position between dependent lip 78 and dependent lip 56, enlarged head 86 is seen to be disposed against a surface of dependent lip 78 with its shaft By passing through a hole 102 in dependent tip 780 A Crasher 104, fitted into a groove 92 in shaft 88 bears against the other side ox dependent tip 78 to retain adjusting screw 84 against displacement with rcspsct to dependent tip 78, and thereby with respect to tab carrier 44, but to allow rotation of adjusting screw 84 about it longitudinal axis. A threaded hole 106 in dependent lip 56 thread ably engages threaded portion 98 of adjusting screw 84. If adjusting scurvy 84 is equipped with left hand threads and if its enlarged head BY is rotated counterclockwise, separation distance D' is decreased and dependent lip 78, along with the . .
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remainder ox tab carrier 44, is moved ruptured in Figs. 1 and 2 as l~dicated by a dashed arriver 108.
Thus a worker acing enlarged head 86 of a adjusting screw 84 in either ox its alternate locations and notating enlarged head 86 in the same direct t on relative to the direction in which he is Pacing produces a displacement ox tab carrier 44 in the same dir~ctlon even though adjusting screw 84 is rotated in opposite directions when considered in a uniform coordinate system.
According to the preceding, it will be seen that a single light load adjustment 34 is capable of permitting adjustment of the light load speed ox a disk of an electric meter while adhering to a unl~orm convention relating the direction of adjustment to the direction of change in disk speed. In addition, the only change which must be made in order to accommodate changing the location or making adjustment ox fight load adjustment 34 prom one end to the other of light load adjustment 34 includes merely relocating adjusting screw 84 prom one ox its alternate locations to the other Theresa.
The use of C-washer 104 to captivate adjusting screw 84 with respect to owe ox the elements betvJeen which it extends is, of course, only one ox the ways in which control ox the separation distance D (or D') may be achieved. In some applications, it may be preferable to employ a biasing coil spring snot shown) fitted over adjusting screw 84 to exert an outward bias force between dependent tip 60 and dependent tip 80 or between dependent lip 56 and dependent lip 78.
I
Having described preferred embodiments ox the - invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modiilcatlons may be ejected therein by one skilled in the art without departing from the scope or spirit ox the invention as defined in the appended claims.
OBJECTS AND SEYMOUR OF THE INVENTION
Accordingly, it is on object of the inrentlon to provide a fight load adjustment or an electric meter which overcomes the drawbacks ox the prior art.
It it a further object of the ln~entlon to provide a fight load adjustment for an electric meter which provides the same sense ox adjustment of disk speed or a given direction ox adjustment notation regardless ox the end of the voltage golf at which the adjustment is performed.
Briefly stated, the present invention preludes a fight load adjustment for an electric meter which includes a frame attachable to a core of a voltage coil and a pole-shading element slldeable with respect to the frame. The pole-shadlng clement includes a windowed plate or a pair of tabs lnterposeable between the core ox thy voltage golf and the rotatable disk and effective to change the direction and magnitude of the torque applied to rotatable disk ox the electric Peter at light load.
A single adjusting screw for the fight load adjustment is placed lo eye I its two altcrnatlYe positions. In either ox its two alternative positions, notation of the head of the adjust screw by a worker aqualung the head produces a displacement ox the windowed plate or tabs which tends to change the disk speed in a sense which it consistent with the con~entlon or the relationship between the directioll of rotation of an adjustment and the change in disk speed.
~3~6~;
. 6 Lowe According to an embodlms~t ox the ln~entio~, there is provided a fight load adjustment ton an electric mater, the electric meter being of the type including at least a voltage golf having a core and a rotatable disk rotatable by a magnetic field at least partly produced by the voltage golf, the core having at least first and second legs disposed within a magnetic influence of the disk, comprising a frame rigidly attachable to the core, a carrier, means for slid ably guiding the carrier on the frame along an axis parallel to a plate ox the disk, pole-shadlng means on the carrier disposable Betsy the first and second legs and the disk and e~ectLve ton at least partly distorting the magnetic field whereby a fight load adjustment torque is applied to the disk, a single light load adjustment screw, first and second alternative locations for the adjustment screw in the frame and the carrier, the first and second locations permitting adjustment access to the adjustment screw prom first and second different locations with respect to the core, the first and second different locations being 180 degrees apart about the core and means at the first location or dlsplaci~g the carrier in a first direction along the axis in response to rotation of the adjustment screw in a first rotational direction and or displacing the carrier in a second opposite direction along the axis in response to notation of the adjustment screw in a second rotational direction, and means at the second location or displacing the carrier in the same first direction along the axis in response to rotation of the adjustment screw in the same first notational 3~6~`~
direction and for displacing the carrier I the same second direction along the axis in response to rotation ox the adjustment screw in the same second notational direction whereby the rotation ox the adjustment screw in one ox the first and second notational directions produces a displacement ox the carrier in the same direction regardless ox whether the single adjustment screw is disposed in the lust or the second alternate locations.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanyl~g drawings, in which like reverence numerals designate the same elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial view ox an electric Peter including a light load adjustment according to an embodiment of the invention.
Fig. 2 is a close-up perspective view ox the light load adjustment ox Fig. 1.
Fig. 3 is a cross cyclone taken along II-II
in Fig. 2 showing the adjustment screw in one of its two alternative locations.
Fig. is a cross section taken along III-III
in Fig. 2 showing the adjustment screw on the other of its two alternate locations.
....
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring Dow to Fig. 1, there is shown, generally at 10 an induction motor in an electric meter. Induction motor 10 includes a voltage cowl 12 on one suds of a rotatable aluminum disk 14 and a current golf 16 on the other side ox rotatable aluminum disk 14. As is conventional, current golf 16 includes a small number ox turns of a heavy conductor 18 passing through a U-shaped magnetic core 20. Typically, two or more turns ox current coil 16 are employed. The load current, or a current proportional to the load current, passes through current coil 16 and thereby produces a magnetic flux in U-shaped magnetic core 20.
Voltage coil 12 consists ox a large number of turns ox a lye insulated wire wound on a center leg 22 of an E-shaped magnetic core 24. The voltage appearing across the load is applied to voltage golf 12. Outer legs 26 and 28 ox Escaped magnetic core 24 are disposed adjacent rotatable aluminum disk 14 generally opposed to legs 30 and 32 ox current coil 16. A light load adjustment 34 is axed to outer legs 26 and 28 adjacent rotatable aluminum disk 14 using, or example, a bolt or rivet 36 through each ox outer lets 26 and 28. The load voltage applied to voltage golf 12 induces a magnetic flux in E-shaped magnetic core 24 which, when combined with the magnetic flux produced in U-shaped magnetic core 20 by the current in current golf 16, produces a torque on rotatable alul~lnum disk 14 which is proportional ~;23~
to the product ox the load current and the ~oltag0.
Although light load adjustment 34 may be of the conductl~e plate or the tab type without departing from the scope ox the invention, or concreteness of description, fight load adjustment 34 is chosen to be ox the type hazing a par ox tabs 38 and 40 of magnetic material overlaying outer legs 26 and 28 respectively Referring now also to Fig. 2, light load adjustment 34 consists of a frame 42 and a tab carrier 44. Frame 42 is affixed to outer lugs 26 and 28. Tab carrier 44 is transversely movable with respect to frame 42 and E-shaped magnetic core 24 to thereby displace tabs 38 and 40 in a direction parallel to the plane of rotatable aluminum disk 14.
Frame 42 includes a transverse bar 46 secured parallel to outer legs 26 and 28 and first and second platform portions 48 and 50 hulling upper beaning surfaces 52 and 54 respecti~aly disposed at fight angles to the plane ox transverse bar 46. Platform portions 48 and 50 are preferably integrally formed with transverse bar 46 using, or example, an appropriately shaped piece of sheet metal in which right angle bends (not shown) may be made to position upper bearing surfaces 52 and 54 in the positions shown. A dependent lop 56 is wormed by a fight angled bend 58 at an end ox upper beaning surface 52 wearer the center of E-shaped magnetic core 24. A
dependent lip 60 is formed by a fight angled bend 62 at an end ox upper beaning surface 54 further from the center of E-shapad magnetic core 24.
Tab carrier 44 includes a connecting bar 64 having a pair of aligned longltud~nal slots 66 and 63 I
thrill hounder rivet 70, affixed in upper beaning surface 52 passes guidlagly through longltudi~al slot 66. Similarly, a shoulder rivet 72 passes guidingly through longitudinal slot 68~ Tab carrier 44 is per~ltted to displace a limited distance transversely in the guldanc0 direction defined by longitudinal slots 66 and 68. A support portion 74 at one end of tab carrier 44 overlies upper beaning surface 52 ox frame 42. Similarly, a second support portion 76 at the other end ox tab carrier 44 overlies upper beaning surface 54 of frame 42. A dependent lip 78 is formed at an end ox support portion 74 further prom the center of shopped magnetic core 24. A dependent tip 80 is wormed at the end ox support portion 76 nearer to tile center of E-shaped magnetic core 24.
A single adjusting screw 84 is employed in one of two alternate locations in light load adjustment 34 to position tab carrier 44 with respect to outer legs 26 and 28. One of the alternate locations for adjustment screw 84 is shown in solid line between dape~dent tips 60 and 80. The other of the alternate locations for adjustment screw 84 is shown in dashed line between dependent tips 56 and 78.
Referring now to the cross section in Fig. 3 showing adjusting screw 84 I its solid fine po81tlon between dependent lip 60 and dependent lip By at the right side of Figs. 1 and 2, it will be noted that adjusting screw 84 includes an enlarged head 86 abutting one surface of dependent tip 60 and a shaft I passing through a hole 90 in dependent tip 60. A
groove 92 retains a C washer 94 against the other ~3~6~i surface of dependent lip 60 to thereby permit rotation of adjustln~ screw I without permitting it to displace with respect to dependent lip 60 that is, with respect to frame 42). A threaded hole 96 thread ably engages a threaded portion 98 on adjusting screw 84. Rotation of adjusting screw 84 is effective to displace dependent lip 80, and the remainder of tab carrier 44 with it, by changing the separation D between dependent lip 60 and dependent tip 80. If adjusting screw 84 has, for example, a left hand thread, rotation ox adjusting screw 84 in the counterclockwise direction is effective to reduce the separation dimension D and to thereby displace tab carrier 44 in the ruptured direction indicated by a solid arrow 100.
Referring now to Fig. 4, showing adjusting screw 84 in its alternate position between dependent lip 78 and dependent lip 56, enlarged head 86 is seen to be disposed against a surface of dependent lip 78 with its shaft By passing through a hole 102 in dependent tip 780 A Crasher 104, fitted into a groove 92 in shaft 88 bears against the other side ox dependent tip 78 to retain adjusting screw 84 against displacement with rcspsct to dependent tip 78, and thereby with respect to tab carrier 44, but to allow rotation of adjusting screw 84 about it longitudinal axis. A threaded hole 106 in dependent lip 56 thread ably engages threaded portion 98 of adjusting screw 84. If adjusting scurvy 84 is equipped with left hand threads and if its enlarged head BY is rotated counterclockwise, separation distance D' is decreased and dependent lip 78, along with the . .
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remainder ox tab carrier 44, is moved ruptured in Figs. 1 and 2 as l~dicated by a dashed arriver 108.
Thus a worker acing enlarged head 86 of a adjusting screw 84 in either ox its alternate locations and notating enlarged head 86 in the same direct t on relative to the direction in which he is Pacing produces a displacement ox tab carrier 44 in the same dir~ctlon even though adjusting screw 84 is rotated in opposite directions when considered in a uniform coordinate system.
According to the preceding, it will be seen that a single light load adjustment 34 is capable of permitting adjustment of the light load speed ox a disk of an electric meter while adhering to a unl~orm convention relating the direction of adjustment to the direction of change in disk speed. In addition, the only change which must be made in order to accommodate changing the location or making adjustment ox fight load adjustment 34 prom one end to the other of light load adjustment 34 includes merely relocating adjusting screw 84 prom one ox its alternate locations to the other Theresa.
The use of C-washer 104 to captivate adjusting screw 84 with respect to owe ox the elements betvJeen which it extends is, of course, only one ox the ways in which control ox the separation distance D (or D') may be achieved. In some applications, it may be preferable to employ a biasing coil spring snot shown) fitted over adjusting screw 84 to exert an outward bias force between dependent tip 60 and dependent tip 80 or between dependent lip 56 and dependent lip 78.
I
Having described preferred embodiments ox the - invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modiilcatlons may be ejected therein by one skilled in the art without departing from the scope or spirit ox the invention as defined in the appended claims.
Claims (5)
1. A light load adjustment for an electric meter, said electric meter being of the type including at least a voltage coil having a core and a rotatable disk rotatable by a magnetic field at least partly produced by said voltage coil, said core having at least first and second legs disposed within a magnetic influence of said disk, comprising:
a frame rigidly attachable to said core;
a carrier;
means for slidably guiding said carrier on said frame along an axis parallel to a plane of said disk;
pole-shading means on said carrier disposable between said first and second legs and said disk and effective for at least partly distorting said magnetic field whereby a light load adjustment torque is applied to said disk;
a single light load adjustment screw;
first and second alternative locations for said adjustment screw in said frame and said carrier, said first and second locations permitting adjustment access to said adjustment screw from first and second different locations with respect to said core, said first and second different locations being 180 degrees apart about said core; and means at said first location for displacing said carrier in a first direction along said axis in response to rotation of said adjustment screw in a first rotational direction and for displacing said carrier in a second opposite direction along said axis in response to rotation of said adjustment screw in a second rotational direction, and means at said second location for displacing said carrier in the same first direction along said axis in response to rotation of said adjustment screw in the same first rotational direction and for displacing said carrier in the same second direction along said axis in response to rotation of said adjustment screw in the same second rotational direction whereby said rotation of said adjustment screw in one of said first and second rotational directions produces a displacement of said carrier in the same direction regardless of whether said single adjustment screw is disposed in said first or said second alternate locations.
a frame rigidly attachable to said core;
a carrier;
means for slidably guiding said carrier on said frame along an axis parallel to a plane of said disk;
pole-shading means on said carrier disposable between said first and second legs and said disk and effective for at least partly distorting said magnetic field whereby a light load adjustment torque is applied to said disk;
a single light load adjustment screw;
first and second alternative locations for said adjustment screw in said frame and said carrier, said first and second locations permitting adjustment access to said adjustment screw from first and second different locations with respect to said core, said first and second different locations being 180 degrees apart about said core; and means at said first location for displacing said carrier in a first direction along said axis in response to rotation of said adjustment screw in a first rotational direction and for displacing said carrier in a second opposite direction along said axis in response to rotation of said adjustment screw in a second rotational direction, and means at said second location for displacing said carrier in the same first direction along said axis in response to rotation of said adjustment screw in the same first rotational direction and for displacing said carrier in the same second direction along said axis in response to rotation of said adjustment screw in the same second rotational direction whereby said rotation of said adjustment screw in one of said first and second rotational directions produces a displacement of said carrier in the same direction regardless of whether said single adjustment screw is disposed in said first or said second alternate locations.
2. A light load adjustment according to claim 1 wherein said means for slidably guiding includes first and second aligned slots in one of said frame and said carrier and first and second rivets in the other of said frame and said carrier said first and second rivets passing through said first and second aligned slots respectively.
3. A light load adjustment according to claim 1 wherein said carrier includes a transverse bar spanning said first and second legs and first and second platform portions disposed substantially at right angles to said bar at opposed ends of said bar, said means for slidably guiding being disposed on said first and second platform portions and engaging aligned slots in said carrier.
4. A light load adjustment according to claim 3 wherein said means at said first location includes a first dependent lip on said frame and a second dependent lip on said carrier substantially parallel to and facing said first dependent lip, said first dependent lip including threaded means engageable by said single light load adjustment screw and said second dependent lip including a through-hole permitting the passage of said adjustment screw therethrough, said means at said second location includes a third dependent lip on said frame and a fourth dependent lip on said carrier substantially parallel to and facing said third dependent lip, said fourth dependent lip including threaded means engage able by said single light load adjustment screw and said third dependent lip including a through-hole permitting the passage of said adjustment screw there-through whereby clockwise rotation of said adjustment screw in said first and second locations produces translation of said carrier in the same direction to thereby produce a change in said torque in the same sense.
5. A light load adjustment according to claim 1 wherein said pole-shading means includes first and second metallic tabs.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/590,973 US4547730A (en) | 1984-03-19 | 1984-03-19 | Light load adjust apparatus for electric meter |
| US590,973 | 1984-03-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1230645A true CA1230645A (en) | 1987-12-22 |
Family
ID=24364493
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000476141A Expired CA1230645A (en) | 1984-03-19 | 1985-03-08 | Light load adjust apparatus for electric meter |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4547730A (en) |
| BR (1) | BR8501164A (en) |
| CA (1) | CA1230645A (en) |
| MX (1) | MX159492A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4760332A (en) * | 1985-10-30 | 1988-07-26 | General Electric Company | Phase lag and light-load adjust for voltage stator |
| US6016054A (en) * | 1997-07-14 | 2000-01-18 | Siemens Transmission & Distribution, Llc | Watt hour meter registration calibration method and apparatus |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2352965A (en) * | 1943-06-11 | 1944-07-04 | Gen Electric | Meter light load adjustment |
| US3496466A (en) * | 1966-03-07 | 1970-02-17 | Hitachi Ltd | Induction type integrating wattmeter having plural separated shunts |
| US3493862A (en) * | 1968-03-28 | 1970-02-03 | Westinghouse Electric Corp | Induction meter having light-load adjuster |
| US4424485A (en) * | 1981-06-10 | 1984-01-03 | Westinghouse Electric Corp. | Fixed light load adjustment assembly for induction meters |
| US4423375A (en) * | 1981-06-10 | 1983-12-27 | Westinghouse Electric Corp. | Self-aligned light load adjustment assembly for induction meters |
| US4424484A (en) * | 1981-06-10 | 1984-01-03 | Westinghouse Electric Corp. | Induction meter having an improved electromagnetic voltage section |
-
1984
- 1984-03-19 US US06/590,973 patent/US4547730A/en not_active Expired - Fee Related
-
1985
- 1985-03-08 CA CA000476141A patent/CA1230645A/en not_active Expired
- 1985-03-15 BR BR8501164A patent/BR8501164A/en unknown
- 1985-03-18 MX MX204653A patent/MX159492A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| MX159492A (en) | 1989-06-16 |
| BR8501164A (en) | 1985-11-12 |
| US4547730A (en) | 1985-10-15 |
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